Speaking as a photographer, here are some issues that may be influencing how blurry your photo is:
available light - the lower the light, the slower the shutter speed in order to capture more light on the sensor; if you don't have a tripod then you're not going to get a sharp image. the lower the light, the higher the ISO; higher ISO brings more unwanted noise and more "approximation" of light (meaning it may not capture exactly what you can see with your eye because it is digitally trying to approximate what the pixels should be based on available light that is able to hit the sensor).
dirty glass - if you didn't clean camera lens area and are getting a blurry image, no surprise there. any oils/grease/dirt from your fingers, hands, clothes, or surfaces you place the phone on will distort the light that is hitting your cameras sensor, and this can result in a blurry image or blurry parts of an image.
extra glass - if you have a case that has extra glass in front of the extra glass built into the iphone's body that is in front of the core lens then you'll get more light distortion and a less sharp image. this is the reason I don't shoot with lens protectors on my dslr lenses... protectors are just another element light has to travel through before it hits the sensor and it can result in a less sharp or more blurry image.
aperture setting - i'm not an expert on the iphone 11 pro's lenses, but I think its lenses are fixed like all smartphone lenses. this means you're always shooting at f/2.4 for the ultra-wide 13mm lens, f/1.8 for the 26mm lens, and f/2 for the 52mm lens. these are very wide apertures, and the wider the aperture the shallower the depth of field (what is sharp and in focus). the advantage is these let in a lot of light, but the disadvantage is that you have to select the focus area properly and hold the camera at the right angle for what you're trying to shoot. for example, if you're trying to photograph a plate of food, and you just photograph the plate from the front instead of directly overhead, then depending on where you focused and how far away you are from the plate part of that plate will be in focus and part of it will be out of focus.
The image you shared above is quite dark, and so any blurryness i would attribute to lack of light and possibly a dirty lens area.